1. Field of the Invention
This invention relates to an improvement in a machine tool such as, for example, a portable lathe for preparing pipe ends for welding, and in particular a tool holder for such a machine tool.
2. Prior Art
Tool holders for machine tools use various forms of slides for adjustably supporting a tool carrier on the tool slide in such a manner that the carrier can be moved along the slide in a precise manner and also can be rigidly secured thereto. It is conventional to configure the tool holder and the tool slide in such a manner that they engage each other along angular bearing surfaces called gibs, which actually form dovetail interlocking slide surfaces.
In a portable lathe machine tool, it is also common to place the tool holders on radially extending tool slides provided on a tool carrier that is rotatable about a cutting axis of symmetry. Such tool carriers are hollow and accommodate a pipe engaging mandrel that extends through the hollow portion of the tool carrier to engage the interior of a pipe to thereby secure the portable lathe in a selected position relative to the pipe end. The tool carrier is driven by a suitable motor and reduction gearing and means are provided to feed the tool carrier into engagement with the pipe end to carry out the pipe end preparation operation. In such portable lathes, it is usual practice to provide a beveling tool, a facing tool and a boring tool to respectively cut a bevel on the pipe end, square the end of the pipe and cut the interior of the pipe to a precise concentric end wall thickness.
It is desirable in such portable lathes to mount the tool carrier on the tool slide in a rigid, adjustable manner, whereby the tool carrier can be rigidly clamped to the tool slide during the cutting operation. Moreover, it is highly desirable to move the tool carrier along the tool slide for adjustment purposes. The requirements for precise location of the tool holder and rigid clamping of the holder to the tool slide requires special consideration of the problems involved. It is therefore an object of this invention to provide a special clamping arrangement between the tool holder and the tool slide of a portable lathe that permits the holder to be rigidly clamping to the tool slide while permitting the tool holder to be adjusted along the tool slide in a simple manner.
It is further an object of this invention to provide a clamping bracket for the tool holder that enables the holder to be rigidly clamped to the tool guide surface provided on the tool carrier.
It is further an object of the invention to provide a clamping arrangement for a tool carrier that is simple and inexpensive to construct.